The present invention relates to an imaging apparatus, an endoscope system, a method of controlling an imaging apparatus, and the like.
An imaging apparatus such as an endoscope is desired to generate a deep-focus image in order to facilitate a doctor's diagnosis. In order to deal with such a demand, the depth of field of an endoscope is increased by utilizing an optical system having a relatively large F-number.
In recent years, an imaging element having about several hundred thousand pixels has been used for endoscope systems. The depth of field of an optical system is determined by the size of the permissible circle of confusion. Since an imaging element having a large number of pixels has a small pixel pitch and a small permissible circle of confusion, the depth of field of the imaging apparatus decreases. In this case, the depth of field may be maintained by reducing the aperture of the optical system, and increasing the F-number of the optical system. According to this method, however, the optical system darkens, noise increases, and the image quality deteriorates. Moreover, the effect of diffraction increases as the F-number increases, so that the imaging performance deteriorates. Accordingly, a high-resolution image cannot be obtained even if the number of pixels of the imaging element is increased. JP-A-2007-13270 discloses technology that changes a pixel binning read process between a movie and a still image.